Situation: A student was running an experiment using local frog spawn, intending to release the frogs after they’d gone through all the phases of metamorphosis. For the sake of convenience, the student used flowering water plants purchased at an aquarium to create the various environments for the frogs. When the experiment was through, the student released the frogs back into their pond by removing the plants and pouring out the entire habitat. A year later, the student came back to find new, non-native plants of the same variety used in the experiment now growing in the frog pond.